Precision-adjustment device



PRECISI ON ADJUSTMENT DEVICE Original Filed 06%. 25. 1922 H 1 2a a 1 29 r: I 1 15 13 3 m -17 22 zeal &

In venfoy VVlZ/ard l7. Eel/an.

Patented May 15, 1928.

i UNITED STATES v I 1,669,698 PATENT OFFICE.

W LLARD n. EARIN, or HUDSON, oHro, ASSIGNOR TO HE RrcoonRrcH COMPANY, on NEW YORK, N. Y., A CORPORATION or NEW YORK.

PRECISION-ADJUSTMENT DEVICE.

Application filed October 25, 1922, Serial No. 596,905.- Renewed March 21, 1928.

This invention relates to precision adjustment devices and is especially applicable to devices adapted for precise angular'ad ustment of parts ofsensitive instruments such as the tuning devicesof radio-telephone sets.

Its chief objects are to provide an im-' proved device, of simple construction, whereby extremely fine adjustment of parts may be had and in which-the adjusted member is automatically secured-in adjusted position;

in the designing of which intricate calculations may be avoided; the parts-ofwhich may be conveniently formed, as by molding them 'of plastic material such as a hard-rub ber compound; and in which all parts may be of such simple form as to provide strength in conjunction with delicacy ofadjustment. A further object is to provide a self-con tained device of such compact construction as to combine strength witheconomy of material. A further object, with respect to embodiments such as that shown in" the accompanying drawings, having a main dial memher and an auxiliary dial member adapted respectively to drive the adjusted member at different relative speeds, is to provide, with a minimum number of parts, a limited range of angular adjustment of the auxiliary dial member with relation to the main dial member, so that the former cannot be turned through more than onerevolution with relation to the latter and uncertainty thus intro duced as to the significance of the dial readings. Still another object is to provide for a decrease of the speed of the adjusted part with relation to. its driving member as it approaches the exact setting desired.

Of the accompanying drawings:

Fig. 1 is a' front elevation of a part of a radio instrument board and, mounted thereon, a precision adjustment device embodying a preferred form of my invention.

Fig. 2 is a vertical section of the same, on the broken line 22 of Fig. 8, with a part broken away.

Fig.3 is a vertical section thereof, on

line 33 of Fig. 2.

Referring to the drawings, 10 is the instrument board, formed with an aperture through which projects, from the front side of the board, the clamping stem 11 of a knobthe stem 11, and the rear faceof said main dial member is concentrically recessed to accommodate a retaining Washer 19 anda spring clip 20-mounted on the. stem 11 and adapted to retainthe principal parts of the device in assembled relation when they are removed from the instrument board, said spring clip fitting 1na circumferentlal groove in sa d stem.

The main dial member 17 is formed with I a forwardly projecting-flange 21 about its circumference, within which is rotatably fitted an annular, auxiliary'dialmember 22' surrounding the base portion of the stem 11, and retained in its seat by the knob-member 12. r

Said auxiliary dial member is formed on its inner periphery with a pair of oppositely pitched, volute, cam surfaces 23, 24 adapted to engage the respective ends of a push-bar or cam-follower 25 slidably mounted between raised guides 26, 27 27, formedon the front face of the main dial member 17 Said cam surfaces are preferably off-set from each other in an axial direction, so that the range oflthe auxiliary dial member need not be unduly limited, and the latter is formed with a shoulder, 23 or 24, at aterminus of each of the cam surfaces, said shoulder connecting the respective ends ofeach cam sur face in the form of device here-shown, and being adapted to strike the side of the pushbar 25 to limit the range offthe auxiliary dial member, as clearly shown as to the shou1- d-er 24 in Fig. 3. When thecam surfaces are axially off-set from each other, as here shown, the push bar 25 is cut 1 awayat "its rear side atone end, as shown at 25, to clear the rear cam, 24, while engaging the front cam, 23, and at the other end is cut away at its front side, as shown at 25", to clear the front'cam, 23, while engaging the rear cam, 24.

The front side of the push-bar 25v is soft rubber ring, 30, is "mounted in? the rear side of saidmember and :adaptedito: bear acting as a crank-pin.

formed with a circular stud 28 slidably and rotatably mounted in a radial groove 29 formed in the rear face of the knob-member 12', said kiiob'member thereby "being adapted to be turned withrelatioritothe maimdial member 17 by the sliding movement of said push-bar, between its guides 26","2'Z,unde'r action of the cam surfaces 23, 24, the stud 28 Saidcam surfaces are preferably so formed that they; will, with} aminimum of-tolerance or-play, engage @the respective ends of; ,the push-bar at all posi tionsof the auxiliary dial-member, although can surfaces, of :simple spiral formgmaybe" used-,- even vwhen the push-bar is off-set from the center of the device as here shown with out: necessitating a very-n great tolerance between saidlysurfaces :and the push-bar.

F r-Csecnring-the main dial member- 17 in adjusted-positions a brake, here shown aswa' against the instrument'board 10, this-form: of ,brake being adapted to avoid cramping thestem=-11 in -the-'aperture ofthe instrument bojard or mi's-aligning ;the, shafts 14:, as distinguished from a brake acting with greater forceat one side of theQstem-11-than-, at the other. The rubber ring i310 is pref-- erably a formed- {of slightly 7 smaller; circumferential length than the groove is to soc-- cupy jand, stretched into the; latter, so thatitsfelasticity retains it thereinwwhen the de-',

vice is removed from theinstrument board.

Theeexposed surface, ofthe mainndial member 17 is provided with a scale 31,;an'd" indicators 82,133 are marked on" the:,instrument-board '10 and theauxiliary- 2dial anem- 1 her 22 respectivelytand adapted tdregister 011,. said, sealer, Both dial; members; :17, 22', and the knobmember; 12, are; formed with wings 17 17f, 22 ,2;2 i"and1-12 12 ,-respec:; tivelyon their outer peripheries, to facilitateturning them. ,In (the operation of ;the de'vice, therparts being assembled as shown clearly in Fig. 2, but preferably with the auxiliarydial mem berc at a position midi-way of its range,athe en tire device, including of coursethe shaft 14;,

' two saidfmenibers are interlocked. against-reL v movement e'xcept as to forces-appliedthereto t-hroughuthe auxiliary dial member 2 22,,since such relative movement 'calls-for a sliding of the push-bar '25 between its guides and such sliding gmoveinent of; the push-bar is prevented bynthe cam :surface '23- er -"245 I against which the'push -bar bearsat itsrespctiveen'ds." Ane-appro imate adjustment being thus obtained, the aukiliary dial member 22 is knob member 12: and with it the ishaft 14', thera'm surface 23*or"24,dependmg upon 7 which way the auxiliary dial member is 'turnechdriviiigthe push-bar 25 and turning the -knob-member-12 at a'very slow relative speed and with a progressively slower relative speed'as-the stud-28n1oves outward .in its slot, 29,-thespeed1ratio increasing not only; 3 because of the-increasing radius fr'om the "center: of" the knob' vto the stud buthecause the :inoveme-nt of the stud becomes; in-- creasingly {oblique -to=-;sai-d radius j By-f a so go setting the main'kdial anember that-Ethe finale adjustment isto -be had near thewlimit -ofi the -.auXiliary.;rdial-1 members 'rangei-of; move IDGIIt," extremel-y' fine adj ustment-may-be had even-tl1ough themain surfaces '23,'-2&z beii'of-f s5 relatively-,high pitch. I flOnnOil whollylimit my claims, howejveryto apparatusrin which: this variable speed ratio is present and run comnensated h e r The cam surfaces 23, 24 mayiirea dilyybe" designed, 5218 by mechanically plattinggthem, 2 and bygiv-ingthem a low :pit'ch the spe'edratio between the auxiliary :dia'l membetand) the member :to .be adjusted ana-y be increased y:

to a valuerapproachi-ng infinity-Without any'195 other change-in: the device andz without such-J weakeningof parts TitS'f'WOlllGlj' be-rnecessaryz'to' accomplish the same; result in:a. gear-driven 5 device, for example, Wherethe? numbera'fof E cogs -would require to be; greatly ,increasedii oo and-- their" size correspondingly ;-reduced, if the sizerof thegdevice: werettoi be :kepti within 1 e reasonable limits: These; f advantages- -ai'e present also in" conjunction witha ipositive drive, which :latteri :hascobv-iouseadvantages" 5 overa frictionally driven;deviceai The :main 1 dial member being' interlocked withtheknob member-except; as to forces applied through the "tt UXl'llfl'I'y dialniemherge thez'brake 80"effectively;v holds said' knob "member "in'a 11 jus'ted position. i J 1 f I a All of the'niajorparts of: thedevice, be'ing 0f simple-form, are adapted-uto' -be "convenientlyimoldedz- The simpleandr'icompact structure of the: device provides #great strength with a minimum of m-ateri-alz :A'll parts .ofthe driving connection between the shaft; l4s=and fthe?aui ziliar y dial memberulie' vwithin the circumference of thie zlattr',-:

which is to 1 say within itsf-area pnoj ectedfi n an axial direction, wliereforethe:device is" self-contained, substantially? all :of its mechanism being enclosed: The knob members. 12 constitutes in effecta crank, 3 which, by reason? ofthe slot 29-is ;of variable? radius"; and lithe walls of said slot constijtute .cam" surfacestadapted to be engagedb :the 'stud 28 in I slidingacon-ta'ct, whereby :s'peed firee duction may be'had' inRadd-itionto thatt-in'cie "t dent to the cam surfaces'23, 24.

Various modifications may be resorted to within the scope of my invention, and 1 do not wholly limit my claims to the specific construction shown. I I

I claim: I

1. A precision adjustment devicecomprising a part to be angularly adjusted, a cam member journaled coaxially with relation thereto and formed with a pair of volute, oppositely pitched, inwardly facing, cam surfaces running at right angles to the axis of said part, a cam follower interposed between said cam surfaces and adapted to be actuated oppositely by them respectively as said cam member is oscillated, and means connecting said cam follower with said part for driving the latter.

2. A precision adjustment device comprising a part to be angularly adjusted, a crank structure thereon formed with a radially disposed recess, a cam follower formed with a stud, said stud being mounted in said recess, a mounting for said cam follower, and a rotatable member provided with a cam surface adapted to actuate said cam follower.

3. A precision adjustment device comprising a part to be angularly adjusted, a slide-' bar operatively connected with and adapted to drive said part, a mounting for said slidebar, and a rotatable member surrounding said part and provided with a cam surface adapted to drive said slide-bar, all driving connections between said part and said ro tatable member being wholly within the axially projected area of the latter.

l. A precision adjustment device comprising a part to be adjusted, an annular member journaled adjacent said part and provided with a pair of oppositely pitched,

volute, circumferentially overlapping cam,

surfaces axially oflset from each other, a cam follower support, mounted thereon within said annular member and provided with oppositely disposed, off-set faces each adapted to engage one of said cam surfaces while clearing the other, said cam surfaces being so formed as to continue approximately in contact with the respective faces of said cam follower as said annular member is turned, and said cam follower being operatively connected with and adapted to drive said part.

5. A precision adjustment device comprising a part to be adjusted, an annular member journaled adjacent said part and provided with a cam surface receding from its axis, a slide-bar mounting, and a slide-bar mounted thereon within saidannular mem her and adapted to drive said part, said cam surface being adapted to drive said slidebar by contact with a transverse face thereof, and said annular member being provided,

at a terminus of said cam surface, with a stop I face adapted to contact a side face of said a cam follower slide-bar to limit the turning of said annular member.

6. A precision adjustment device comprising a part to be angularly adjusted, a

main dial member journaled concentrically withrelation thereto, means for securing said maindial member in different angular positions, an auxiliary dial member rotatably mounted on said main dial member, and means including a cam for driving said part with relation to said main dial member when said auxiliary dial member is turned.

7 A precision adjustment device comprising a part to be angular-1y adjusted, a main dial member journaled concentrically with relation to said part, means for securing said main dial member in different angular positions, an auxiliary dial member journaled on said main dial member, surrounding said part, and internally formed with a cam surface receding from its axis, and a cam follower mounted on said main dial member within said auxiliary dial member and adapted to be actuated bythe cam surface of the latter, said cam follower being operatively connected with and adapted, under action of said cam surface, to drive said part with relation to said main dial member as said auxiliary dial member is turned.

8. A precision adjustment device comprising a part to beangularly adjusted a main dial member journaled concentrically with relation to said part, means for securing said main dial member in different angular positions, an annular, auxiliary dial member journaled on said main dial member and internally provided with a pair of oppositely pitched cam surfaces receding from its axis, and a camfollower mounted on said main dial member within said auxiliar dial member, opposite faces of said cam fo lower being adapted to be engaged by said cam surfaces respectively, and said cam follower being operatively connected with and adapted to drive said part with relation to said main dial member as said auxiliary dial member is turned.

, 9. A precision adjustment device comprising a part to be angularly adjusted, a main dial member journaled concentrically with relation thereto, an auxiliary dial member journaled on said main dial member, and

means operatively connecting said auxiliary varying speed ratio, when said. auxiliary dial member is turned.

10. In radio apparatus, in combination with an instrument board and a shaft positioned at right angles thereto and requiring to be angularly adjusted, a precision adjustment device for said shaft comprising a. knob member secured to said shaft, the head of said knob member being formed on its member coaxially journaled With relati'dn' to said auxiliarydia1' member,-=ada;ptdd 1:0 198 tweefl 'aid-matifi difil membefandSaid board}? With a stud, said stud being mountfl in the an aniiula'rq -auxiliavywdial meinbef Coaxialgroove of said knob-member.

rededing fmm -its axis-yanammmwfollwers 7 WIBLARDD. EAKIN.-# 

